Managing and securing the links is Proxy-SG from Blue Coat Systems Inc. of Sunnyvale, Calif. The gateway appliance sits at each network connection, filtering incoming and outgoing traffic.

SPAWAR uses ProxySG mainly to filter uniform resource locators, said John Sellers, director of federal sales. The appliances are centrally managed through Blue Coat's Director console, which can set policy based on individual users, groups, time of day, location, content type or other attributes.

ProxySG also monitors peer-to-peer file sharing, video streaming and instant messaging. It has up to 300 Mbps of throughput and caches content to speed performance.

Crowe said the proxy appliance is part of a trend toward making network defense preventive rather than reactive.